Process Economics Program Report 199
Plastics Reclamation and Recycling 199
Published: January 1992
In the rapidly growing business of plastics recycling, profit opportunities vary with the type of plastic. Polyethylene (PE), polystyrene (PS) and polyethylene terephthalate (PET) are now being recycled in large volumes. PET bottles are widely used for beverages (more than 710 million pounds were used in 1990 in the United States alone). Some states encourage their collection with a bottle deposit. We estimate that PET bottles can be ground, washed and separated from PE base cups and aluminum, dried and pelletized in a 50 million pound-per-year plant for about $0.20 per pound less than the price of virgin PET pellets.
However, less expensive plastics are more difficult to recycle economically. PE milk bottles or PS foam food-service containers can be converted to flakes or pellets, but at current prices, the return on investment is less than 25%. The cost of the used plastic received at the processor's plant is a large part of the processor's total cost. Until better automatic machines are developed, the cost of manually removing extraneous matter is also significant.
Recycled plastics have nearly all the desirable properties of virgin plastics. They can be blended with virgin plastics or used in a composite structure, sandwiched between layers of virgin plastic.
Commingled plastics that are not separated can be processed into mixed plastics products for a small but growing market. Additives and compatibilizers improve the product properties, but contribute significantly to the cost.
The plastics recycling business, which saves energy, recovers valuable materials for reuse, and spares overflowing landfills some of their ever increasing load, includes three parts:
- the collection, sorting and transportation to a processing center
- the processing itself
- the development of markets for recycled plastics.
Slow growth in the first area is limiting recycling overall. However, new equipment and techniques--some adapted from other industries--are being developed rapidly for processing used plastics.
This report reviews the state of the art in all three segments of this rapidly changing field. It focuses on the technology and economics of processing--the grinding, cleaning, drying and reshaping of plastics into a reusable form. Recycling equipment and techniques are critically reviewed and compared. Because polyethylene (PE), polystyrene (PS) and polyethylene terephthalate (PET) are recycled in the largest volume, they are evaluated in the greatest detail.
Designed to help companies assess the impact of re-cent developments on their own operations, this report will also be of use to companies that are considering plastics recycling, as well as companies already engaged in various segments of the plastics business.